Lump charcoal burns away almost entirely. Kingfords, etc leave a ton of ash due to the binders that do not burn away. If you use lump, you have much less ash, much higher heat, lower burn times though but a much cleaner flavor AND the ability to add more charcoal on the fly, it is however more expensive BUT you can get to choose the wood used (hickory and oak burn the longest, mesquite charcoal burns wicket fast and hot but has that distinct flavor).

I prefer propane...j/k, charcoal all the way. I am up and running in 20 minutes with my chimney starter, about 5-10 minutes more then it takes to heat up a gas grill. And cleaning the old ashes, all good charcoal grills have ash catches that only require cleaning every 3-4 uses.